The physical chemistry of sulphide phosphors

In order to make possible a description of the formation of phosphors by the concepts of physical chemistry, simplification of the chemical composition of the system and the conditions of preparation is indispensable. For a particular case, namely, ZnS, it is shown how preparation under controlled conditions may lead to a knowledge of the microstructure of the solid, and thence to an insight into the nature of the centres of luminescence and traps. It is shown that this knowledge is a necessary condition for the complete physico-chemical description of the formation of the phosphor in equilibrium with an atmosphere or a melt.